/**
 * Copyright (c) 2015 ibenchu.com. All Rights Reserved.
 *
 * YyFramework
 *
 * JsMD5.java created on 下午11:27
 *
 * @author yuanguozheng
 * @version 1.0.0
 * @since 15/8/18
 */
package com.coderyuan.yyframework.hash;

/**
 * JsMD5
 *
 * @author yuanguozheng
 */
public class JsMD5
{
  /*
   * A Java implementation of the RSA Data Security, Inc. JsMD5 Message
   * Digest Algorithm, as defined in RFC 1321.
   * Based on the JavaScript implementation of Paul Johnston
   *      Copyright (C) Paul Johnston 1999 - 2000.
   *      See http://pajhome.org.uk/site/legal.html for details.
   * Java Version by Thomas Weber (Orange Interactive GmbH)
   */

    /*
     * Convert a 32-bit number to a hex string with ls-byte first
     */
    String hex_chr = "0123456789abcdef";
    private String rhex(int num)
    {
        String str = "";
        for(int j = 0; j <= 3; j++)
            str = str + hex_chr.charAt((num >> (j * 8 + 4)) & 0x0F) + hex_chr.charAt((num >> (j * 8)) & 0x0F);
        return str;
    }

    /*
     * Convert a string to a sequence of 16-word blocks, stored as an array.
     * Append padding bits and the length, as described in the JsMD5 standard.
     */
    private int[] str2blks_MD5(String str)
    {
        int nblk = ((str.length() + 8) >> 6) + 1;
        int[] blks = new int[nblk * 16];
        int i = 0;
        for(i = 0; i < nblk * 16; i++) {
            blks[i] = 0;
        }
        for(i = 0; i < str.length(); i++) {
            blks[i >> 2] |= str.charAt(i) << ((i % 4) * 8);
        }
        blks[i >> 2] |= 0x80 << ((i % 4) * 8);
        blks[nblk * 16 - 2] = str.length()*8;

        return blks;
    }

    /*
     * Add integers, wrapping at 2^32
     */
    private int add(int x, int y)
    {
        return ((x&0x7FFFFFFF) + (y&0x7FFFFFFF)) ^ (x&0x80000000) ^ (y&0x80000000);
    }

    /*
     * Bitwise rotate a 32-bit number to the left
     */
    private int rol(int num, int cnt)
    {
        return (num << cnt) | (num >>> (32 - cnt));
    }

    /*
     * These functions implement the basic operation for each round of the
     * algorithm.
     */
    private int cmn(int q, int a, int b, int x, int s, int t)
    {
        return add(rol(add(add(a, q), add(x, t)), s), b);
    }
    private int ff(int a, int b, int c, int d, int x, int s, int t)
    {
        return cmn((b & c) | ((~b) & d), a, b, x, s, t);
    }
    private int gg(int a, int b, int c, int d, int x, int s, int t)
    {
        return cmn((b & d) | (c & (~d)), a, b, x, s, t);
    }
    private int hh(int a, int b, int c, int d, int x, int s, int t)
    {
        return cmn(b ^ c ^ d, a, b, x, s, t);
    }
    private int ii(int a, int b, int c, int d, int x, int s, int t)
    {
        return cmn(c ^ (b | (~d)), a, b, x, s, t);
    }

    /*
     * Take a string and return the hex representation of its JsMD5.
     */
    public String calcMD5(String str)
    {
        int[] x = str2blks_MD5(str);
        int a = 0x67452301;
        int b = 0xEFCDAB89;
        int c = 0x98BADCFE;
        int d = 0x10325476;

        for(int i = 0; i < x.length; i += 16)
        {
            int olda = a;
            int oldb = b;
            int oldc = c;
            int oldd = d;

            a = ff(a, b, c, d, x[i+ 0], 7 , 0xD76AA478);
            d = ff(d, a, b, c, x[i+ 1], 12, 0xE8C7B756);
            c = ff(c, d, a, b, x[i+ 2], 17, 0x242070DB);
            b = ff(b, c, d, a, x[i+ 3], 22, 0xC1BDCEEE);
            a = ff(a, b, c, d, x[i+ 4], 7 , 0xF57C0FAF);
            d = ff(d, a, b, c, x[i+ 5], 12, 0x4787C62A);
            c = ff(c, d, a, b, x[i+ 6], 17, 0xA8304613);
            b = ff(b, c, d, a, x[i+ 7], 22, 0xFD469501);
            a = ff(a, b, c, d, x[i+ 8], 7 , 0x698098D8);
            d = ff(d, a, b, c, x[i+ 9], 12, 0x8B44F7AF);
            c = ff(c, d, a, b, x[i+10], 17, 0xFFFF5BB1);
            b = ff(b, c, d, a, x[i+11], 22, 0x895CD7BE);
            a = ff(a, b, c, d, x[i+12], 7 , 0x6B901122);
            d = ff(d, a, b, c, x[i+13], 12, 0xFD987193);
            c = ff(c, d, a, b, x[i+14], 17, 0xA679438E);
            b = ff(b, c, d, a, x[i+15], 22, 0x49B40821);

            a = gg(a, b, c, d, x[i+ 1], 5 , 0xF61E2562);
            d = gg(d, a, b, c, x[i+ 6], 9 , 0xC040B340);
            c = gg(c, d, a, b, x[i+11], 14, 0x265E5A51);
            b = gg(b, c, d, a, x[i+ 0], 20, 0xE9B6C7AA);
            a = gg(a, b, c, d, x[i+ 5], 5 , 0xD62F105D);
            d = gg(d, a, b, c, x[i+10], 9 , 0x02441453);
            c = gg(c, d, a, b, x[i+15], 14, 0xD8A1E681);
            b = gg(b, c, d, a, x[i+ 4], 20, 0xE7D3FBC8);
            a = gg(a, b, c, d, x[i+ 9], 5 , 0x21E1CDE6);
            d = gg(d, a, b, c, x[i+14], 9 , 0xC33707D6);
            c = gg(c, d, a, b, x[i+ 3], 14, 0xF4D50D87);
            b = gg(b, c, d, a, x[i+ 8], 20, 0x455A14ED);
            a = gg(a, b, c, d, x[i+13], 5 , 0xA9E3E905);
            d = gg(d, a, b, c, x[i+ 2], 9 , 0xFCEFA3F8);
            c = gg(c, d, a, b, x[i+ 7], 14, 0x676F02D9);
            b = gg(b, c, d, a, x[i+12], 20, 0x8D2A4C8A);

            a = hh(a, b, c, d, x[i+ 5], 4 , 0xFFFA3942);
            d = hh(d, a, b, c, x[i+ 8], 11, 0x8771F681);
            c = hh(c, d, a, b, x[i+11], 16, 0x6D9D6122);
            b = hh(b, c, d, a, x[i+14], 23, 0xFDE5380C);
            a = hh(a, b, c, d, x[i+ 1], 4 , 0xA4BEEA44);
            d = hh(d, a, b, c, x[i+ 4], 11, 0x4BDECFA9);
            c = hh(c, d, a, b, x[i+ 7], 16, 0xF6BB4B60);
            b = hh(b, c, d, a, x[i+10], 23, 0xBEBFBC70);
            a = hh(a, b, c, d, x[i+13], 4 , 0x289B7EC6);
            d = hh(d, a, b, c, x[i+ 0], 11, 0xEAA127FA);
            c = hh(c, d, a, b, x[i+ 3], 16, 0xD4EF3085);
            b = hh(b, c, d, a, x[i+ 6], 23, 0x04881D05);
            a = hh(a, b, c, d, x[i+ 9], 4 , 0xD9D4D039);
            d = hh(d, a, b, c, x[i+12], 11, 0xE6DB99E5);
            c = hh(c, d, a, b, x[i+15], 16, 0x1FA27CF8);
            b = hh(b, c, d, a, x[i+ 2], 23, 0xC4AC5665);

            a = ii(a, b, c, d, x[i+ 0], 6 , 0xF4292244);
            d = ii(d, a, b, c, x[i+ 7], 10, 0x432AFF97);
            c = ii(c, d, a, b, x[i+14], 15, 0xAB9423A7);
            b = ii(b, c, d, a, x[i+ 5], 21, 0xFC93A039);
            a = ii(a, b, c, d, x[i+12], 6 , 0x655B59C3);
            d = ii(d, a, b, c, x[i+ 3], 10, 0x8F0CCC92);
            c = ii(c, d, a, b, x[i+10], 15, 0xFFEFF47D);
            b = ii(b, c, d, a, x[i+ 1], 21, 0x85845DD1);
            a = ii(a, b, c, d, x[i+ 8], 6 , 0x6FA87E4F);
            d = ii(d, a, b, c, x[i+15], 10, 0xFE2CE6E0);
            c = ii(c, d, a, b, x[i+ 6], 15, 0xA3014314);
            b = ii(b, c, d, a, x[i+13], 21, 0x4E0811A1);
            a = ii(a, b, c, d, x[i+ 4], 6 , 0xF7537E82);
            d = ii(d, a, b, c, x[i+11], 10, 0xBD3AF235);
            c = ii(c, d, a, b, x[i+ 2], 15, 0x2AD7D2BB);
            b = ii(b, c, d, a, x[i+ 9], 21, 0xEB86D391);

            a = add(a, olda);
            b = add(b, oldb);
            c = add(c, oldc);
            d = add(d, oldd);
        }
        return rhex(a) + rhex(b) + rhex(c) + rhex(d);
    }

}
